1. Field of the Invention
This invention is applicable within the industry dedicated to the manufacturing of systems, apparatii, devices and auxiliary elements applied as components for road safety equipments incorporated on roads and similar locations.
2. Background Art
Metallic safety barriers.—Various types of vehicle detention systems exist in the Art, understanding by such, to mean all devices installed on a road with the purpose of providing detention and redirection of a vehicle which leaves the road whilst out of control, thus reducing the severity of produced accidents, in such away, that it restricts the damages and injuries both of their occupants and of the rest of the road users and of other persons or objects located in the neighbourhood.
The most common detention system in our roads and motorways are metallic safety barriers, used at road sides and circulation-lane division rails. The purpose of safety barriers is to resist vehicle impacts, preventing vehicles from crossing through them and thus guaranteeing protection to third parties and in turn, producing a controlled redirecting and deceleration in such a way that the vehicle comes out stably from the impact and continues forward at reduced speed alongside the detention system in the original direction of the traffic, thus guaranteeing the safety of the vehicle occupants and that of other road users
According to the applicable standardization system in existence (EN 1317-2 in Europe and NCHRP 350 in the U.S.), safety barriers are subjected, prior to commercial use, to standardized real scale impact tests in which impacts, between a type vehicle and a detention system are carried out under control, thus facilitating a qualitative and quantitative evaluation of its behaviour. A detention system is considered to meet satisfactorily a real scale impact test when the acceptance requirements and criteria defined in the standard as regards detention level, impact severity, deformation and exit angle are met, and in consequence, assures appropriate safety conditions, mainly to the impacted vehicle occupants and to third parties. It is therefore guaranteed that a detention system is capable of retaining a specific type vehicle.
According to said standards, a high detention system (specifically designed to receive heavy vehicle impact, such as lorries and coaches) shall meet real scale impact tests, both of heavy vehicles (lorries and coaches) or heavy tourisms or of light vehicles (light tourisms). This allows the detention systems to additionally assure the safety of light vehicles, which constitute the most frequent type of accidents. For example, according to European Standard EN 1317-2, the N2 level of detention requires compliance with test TB32 (1.500 Kg car weight impact, at a speed of 110 Km/hr, and an approximation angle against the detention system of 20°.) plus test TB11 (900 Kg car weight impact at a speed of 100 Km/hr, and with an approximation angle against the detention system of 20°.).
All elements which constitute the safety barriers are generally capable of reacting similarly and together by means of deformation, versus the impact both of a light and a heavy vehicle.
Metallic safety barriers correspond to the union of three basic metallic elements:                1st.—Fences or railings, longitudinal elements horizontally arranged at one or various levels at specific height and in a continuous manner, the function of which is that of retaining and guiding impacting vehicles, preventing them from penetrating across, restricting the transversal deformation and guiding them in such a manner, that they can be redirected appropriately by the system. The railing may present different configurations: one or various longitudinal profiles with open or almost closed cross section, with double or triple wave or in “C” or “sigma” shape, joined to the post by means of a separating element; tensed metallic cables or rods attached directly to the post; longitudinal profiles in the shape of double or triple wave joined at their bottom part to metallic sheets capable of free movement and calibrated to present a certain resistance versus impact.        2nd.—The Post, vertically arranged at regular intervals and attached to the fence (fences) or rail (railings), the function of which is to support and keep the fence (fences) or rail (railings) of the barrier at a specific height during impact. The posts are generally metallic profiles with “C”, “U”, “I”, “Sigma” or “Z” cross sections, round or rectangular tubular cross sections or other types of cross sections, that are inserted in an embankment or centre circulation-lane division railing in such a way, that part of its length is embedded in the ground or else through a plate with anchorage bolts inserted in the ground. Faced with the impact of a vehicle and based on the energy of said impact, the post deforms in a greater or lesser degree, bending and/or twisting as regards the embedding or anchorage section.        3rd.—The separating element is an intermediate connection part between a fence or railing and the post, the function of which is as follows:        (I) To join, at a set height, the fence or railing to the attachment post,        (II) to act as spacing element between said fence or railing and the post so as to prevent the entanglement of the vehicle wheel to the post during impact against the bather and        (III) to maintain the fence or railing height as the post deforms by flexure, in such a manner that contact with the vehicle is produced without the appearance of a difference in height of its centre of gravity as regards the railing, which may create a certain tendency of the vehicle to overturn.        
Specific types of separators, especially non-stiff separators used in high detention stiff metallic bathers, comply with an additional function, that of                (IV) attenuating or absorbing part of the impact energy and contributing to the redirecting of the vehicle during impact. In this latter case, the separator receives the name of energy absorber. The absorbing function of the separator is characteristic of high detention bathers since said barriers present a very robust or stiff basic structure made up of the rail or rails and robust posts arranged at a short distance, capable of retaining heavy vehicles, and because of this, said structure is too stiff for the impact of light vehicles. The separator-absorber is specifically designed to reduce the impact severity of light vehicles against these rigid basic structures, tempering the contact with the post and aiding the redirecting of the vehicle. On some occasions, this element consists of a single item or else of an assembly mounted as from flat bars and/or metallic profiles formed in a more or less complex manner, or in square or rectangular open or closed, cross sectional tubular profiles.        
On some occasions, bathers with no separating elements are to be found, the railings being directly attached to the post.
The problem of motorcyclists with metallic safety bathers. In the majority of cases, metallic safety bathers are designed and tested to retain only the impact of vehicles with four or more wheels but in general, they do not take into account the safety of more vulnerable road users, such as motorcyclists and cyclists.
The most common and serious collision of a motorcyclist against a safety barrier is that produced by the loss of verticality of the motorcycle, fall of the motorcyclist, the divergent path of the motorcycle and motorcyclist with sliding of the motorcyclist over the pavement and impact of the motorcyclist's body against the safety barrier, or his penetrating across through the same, and impacting against infrastructural obstacles placed behind the same. The fatal consequences and very sever injuries produced in this type of accidents are in the majority of cases due to injuries in the head and neck of the motorcyclist.
Spanish Standard UNE 135 900 stipulates the test procedures and acceptance criteria for devices installed on metallic barriers for the protection of motorcyclists or else for barriers designed to assure the safety of motorcyclists, which evaluates the body impact behaviour of a motorcyclist who collisions against the system at a set speed and slides over the pavement surface. The test procedure consists in a collision at real scale, with an instrumented dummy—launched against the system at 60 km/hr and at a 30° incidence angle. The efficiency and acceptance criteria parameters related to the severity of impact on the motorcyclist's body is materialized by means of various biomechanical and bio-accurate Indexes measured on the head (accelerations) and on the neck (forces and moments) of the dummies.
In said real scale collision tests with dummies simulating the body of motorcyclists, the dummies are launched against the barrier sliding over the pavement face upwards, at floor level, totally extended with arms parallel to the trunk of their body and headfirst. Impacts on the area of the post are carried out as well as in the centre of the space or middle point of the longitudinal space between two consecutive posts. The vertebral axis of the dummy is parallel to the impact direction, forming 30° as regards the longitudinal alignment of the safety barrier. Consequently, the primary impact (which is the most sever) is produced on the dummy's head (provided with a protection helmet), in such a manner, that the most important and harmful effects on the same are:                (i) the “jerk” of the head that is evaluated by means of the so called HIC index, which is a magnitude proportional to the accelerations experienced by the centre of the dummy's head, and        (ii) the stresses on the neck, including all the forces and moments. The neck is very vulnerable in this type of impacts, mainly due to the compression forces in the vertebral axis direction of the dummy, which in Spanish Standard UNE 135 900 is identified as Fz.        
When a safety barrier, including a protection system for motorcyclists, or else a safety barrier that is specifically designed for the safety of these users, satisfactorily passes the Standard UNE 135 900 tests, complying with all the acceptance criteria, it is considered that safety versus the impact of motorcyclists and cyclists is guaranteed.
According to establishments in Spanish Standard UNE 135 900, all safety bathers that include a protection system for motorcyclists or else all safety bathers specifically designed for the safety of these users, shall additionally assure its behaviour versus impact of two or more wheeled vehicles according to European Standard EN 1317-2.
Protection systems for motorcyclists in safety metallic barriers currently in existence. Two types of devices for motorcyclists protection in metallic safety barriers have been traditionally in use: screen or horizontal continuous profile, and on the other                1. Impact absorbers. These are devices punctually installed around the barrier posts as a covering to reduce the severity of the impact on the motorcyclist against the post. Its efficiency is quite reduced (does not exceed 30 Km/hr) and does not prevent the passing of the motorcyclist beneath the railing, penetrating across the barrier.        2. Continuous systems. These are devices installed in a continuous manner in longitudinal direction to the bather, that function by detaining and redirecting the body of the motorcyclist during impact, preventing both direct impact against the post and penetration across the bather, impacting against the obstacle or drop in the terrain that is being protected by the bather. The continuous systems also operate as punctual systems and are in general, more efficient than previous ones.        
Continuous systems are generally made up of a horizontal continuous member intended to retain the impact of the motorcyclist and are always situated below the railing (though sometimes they project upwards superimposed on the bather over the railing) covering the vertical space between the same and the level of the terrain and are attached to the barrier, either through supporting parts arranged at regular intervals and connected to the bather, either on the post, on the railing or on the separator or else are attached to the horizontal continuous member directly to the post or to the safety barrier railing.
This continuous horizontal member is generally a metallic profile, a plastic profile, various parallel metallic or plastic profiles, one or various plastic tubes, a plastic continuous horizontal girder embedding the posts or else a simple plastic mesh placed between the posts. The horizontal member may be a metallic girder with different profile (Type A double wave railing profile, type B double wave railing profile, flat trapezoidal profile . . . ). When the profile, either metallic or of any other material, considered according to its placement position on the barrier, presents reduced width in relation to its height (e.g. in a minor ratio of 100:370) and a good part of the profile is flat or of reduced relief, the profile receives the name of screen.
The more generally used systems are the metallic, double wave profile type and trapezoidal screens (the surface of which is mainly flat with corresponding flanges forming angles below 90° at their ends, said flanges capable of being rounded).
The continuity of the horizontal element, made up of finite length profiles is generally achieved by means of partial overlapping of the adjacent profiles and screwed joints on said overlaps.
The support parts of the screens or profiles present various configurations, and in general receive the name of arms. They are normally metallic and attached by means of screwed joints, on one side, to the side, either directly to the separator, with the joint screw between the railing and the separator, or else directly to the railing or post.
The support parts or arms are generally attached both to the motorcyclist impact detention horizontal element and to the safety barrier by means of screwed joints.
In real scale impact tests with the previously described dummies, with continuous metallic systems of the ones constituted by a bottom horizontal continuous metallic profile and support metallic arms arranged at regular intervals, the collision of the dummy is produced against the bottom continuous horizontal element which is the one that maintains contact with the dummy throughout all the impact, guiding it during the reductive phenomenon and until it separates from the system.
The support parts of the horizontal profile or arms are capable of deforming, rotating and bending towards the front part of the barrier post (the one opposite the side of the traffic), thus providing the system with sufficient capacity of transversal deformation absorbing the impact under control conditions and redirecting the dummy's body. The transversal deformation is restricted by the distance between the rear part of the arm and the front part of the post, until contact of the arm situated facing the post, is produced with said post. FIG. 14 shows successive stages of this type of behaviour in the continuous metallic system that is the object of the present description.
Main problems that remain unsolved in the continuous metallic systems in existence, constituted by a bottom continuous horizontal profile and support arms at regular intervals. Within the continuous systems, the behaviour of which is in general superior to that of impact absorbers, the most frequent and most effective are the metallic systems constituted by a continuous horizontal profile or element placed below the railing of the safety bather, covering the vertical space between its bottom end and the terrain, due to their excellent benefit/cost ratio.
However, according to the efficiency parameters established in Spanish Standard UNE 135 900 to evaluate the behaviour of the protection systems for motorcyclists in metallic safety barriers, defined as from biomechanical indexes that accurately reproduce the predictable damages in the bodies of motorcyclists, the previously indicated continuous metallic systems pose the following problems:                (i) Possibility of freeway through the system in impacts in the centre of the space. When the distance between consecutive posts of the safety barrier exceeds 2 m, the deformation of the screen during an impact in the centre of the space is enormous, causing bagging of the motorcyclist's body, who, by either raising the screen or profile and/or bending it, can totally or partially cross through the screen or profile, with the subsequent probable risk of impact against the post, the cutting of the actual screen or profile and of collision with the infrastructural dangers the barrier is protecting, which are situated behind the same.        (ii) Entanglement of an extremity below the screen. Due to the fact that a free gap, however small, always remains between the screen or profile and the level of the terrain, and that during the tests (and also in real life), the arm of the dummy/motorcyclist is extended parallel to the body, both his hand and his wrist may become entangled between the bottom edge and the screen or profile and the terrain.        (iii) High vertical compression value of the neck. Since in existing systems, the bottom continuous metallic profiles and screens are vertically arranged, during impact, the first contact of the head with the screen or profile is produced at a vertical plane and with this, very high values are reached in the compression force of the neck Fz in direction to the vertebral axis of the dummy's body (that coincides with the impact trajectory) which originates due to the reaction of the profile or screen on the head of the dummy, often over the maximums tolerated by the human body.        